Aliphatic polycarbonate is excellent in oxygen-barrier property, transparency, and the like, but is difficult to use as a single film due to a low Tg, which needs to be, in most cases, laminated with other resin at the time of use. However, in order to make the aliphatic polycarbonate be laminated with other kinds of resins such as PE, PP, or the like, when an appropriate adhesive capable of adhering two kinds of resins are used for lamination or coextrusion, a resin for a tie layer capable of adhering the two kinds of resins is needed.
The polylactic acid-based polymer may be variously used as films, sheets, fibers, or the like, due to biodegradability and inherent physical properties thereof, but is limited in a packaging field requiring prevention of acidification due to large oxygen permeability thereof.